Compressor with improved oil separation

ABSTRACT

An oil separator for a fluid compressor is disclosed. The oil separator includes a housing having a generally cylindrical cavity formed therein. A wall is disposed in the cavity to form an inlet side of the cavity and an outlet side of the cavity. A conduit extends through the wall and provides a fluid communication path between the inlet side and the outlet side of the cavity. The inlet side of the cavity facilitates the separation of an oil from a fluid, wherein the separated oil is returned to an oil reservoir formed in the housing, and the fluid is provided substantially free of oil to an associated refrigeration circuit.

FIELD OF THE INVENTION

The present invention relates to a compressor, and more particularly to an oil separator for a compressor adapted to separate lubricating oil from a gaseous medium.

BACKGROUND OF THE INVENTION

Compressors used in refrigeration and air conditioning systems such as swashplate type compressors and scroll compressors, for example, typically include a lubricating oil mist suspended in a gaseous refrigerant medium. Such compressors are often employed in automotive air conditioning systems. In a typical automotive air conditioning system, the oil-refrigerant mixture enters the compressor through a suction port and is compressed therein. The compressed, high pressure oil-refrigerant mixture exits the compressor through a discharge port to travel through a refrigeration circuit before returning to the suction port to begin another cycle through the compressor and the refrigeration circuit.

Although the oil circulates through the entire refrigeration circuit, it is only needed in the compressor to lubricate the moving parts therein. Oil that remains suspended in the refrigerant as it travels throughout the refrigeration circuit can reduce the performance of the refrigeration circuit. For example, oil that travels through a heat exchanger in the refrigeration circuit is known to wet internal surfaces of the heat exchanger. Oil disposed on the internal surfaces of the heat exchanger reduces the heat transfer rate between the heat exchanger an the refrigerant. Accordingly, the compressor and other components of the refrigeration or the air conditioning system must have additional capacity to overcome the reduced heat transfer rate caused by oil flowing throughout the refrigeration circuit.

Also, oil that remains suspended in the refrigerant flowing through the refrigeration circuit is not available to lubricate the moving parts of the compressor. The compressor is susceptible to increased wear and seizure potential as a result of the reduced amount of available lubricating oil.

To combat these problems, an oil separator can be added to the compressor. Such an oil separator is typically positioned between the discharge port and a condenser inlet. The oil separator functions to separate the suspended oil from the gaseous refrigerant and militate against the oil from exiting the compressor and circulating through the refrigeration circuit. However, prior art oil separators such as U.S. Pat. No. 6,551,072 to Ota et al. and U.S. Pat. No. 7,281,913 to Oiwake typically increase the overall size of the compressor, limit the available positions for mounting the compressor, and do not significantly reduce the amount of oil required to adequately lubricate the compressor.

It would be desirable to produce an oil separator for a fluid compressor, wherein a space requirement is minimized, and an oil separation efficiency and available mounting positions of the compressor are maximized.

SUMMARY OF THE INVENTION

Compatible and attuned with the present invention, an oil separator for a fluid compressor, wherein a space requirement is minimized, and an oil separation efficiency and available mounting positions of the compressor are maximized, has surprisingly been discovered.

In one embodiment, an oil separator for a fluid compressor comprises a housing having a cavity formed therein; a wall disposed in the cavity to divide the cavity into an inlet side and an outlet side, the inlet side including a fluid inlet channel and at least one fluid drain channel, and the outlet side including a fluid outlet channel, wherein the inlet side of the cavity facilitates the separation of an oil from a fluid; and a conduit extending through the wall providing a fluid communication path between the inlet side and the outlet side of the cavity.

In another embodiment, a fluid compressor comprises a housing having a discharge port and at least one oil reservoir formed therein; a generally cylindrical cavity formed in the housing forming an oil separator, the oil separator further comprising: a wall disposed in the cavity to divide the cavity into an inlet side and an outlet side, the inlet side including a fluid inlet channel providing fluid communication between the discharge port and the inlet side, and at least one fluid drain channel providing fluid communication between the at least one oil reservoir and the inlet side, the outlet side including a fluid outlet channel adapted to provide fluid communication between the outlet side and a refrigeration circuit, wherein the inlet side of the cavity facilitates the separation of an oil from a fluid; and a conduit extending through the wall providing a fluid communication path between the inlet side and the outlet side of the cavity.

A method for separating a lubricant from a refrigerant in a fluid compressor comprising the steps providing a housing for the compressor having a generally cylindrical cavity, a discharge port, and at least one oil reservoir formed therein; providing a wall to divide the cavity into an inlet side and an outlet side, the inlet side including a fluid inlet channel providing fluid communication between the discharge port and the inlet side of the cavity, and at least one fluid drain channel providing fluid communication between the at least one oil reservoir and the inlet side of the cavity, the outlet side including a fluid outlet channel providing fluid communication between the outlet side of the cavity and an associated refrigeration circuit; providing a conduit extending through the wall providing a fluid communication path between the inlet side and the outlet side of the cavity; causing a refrigerant-oil fluid mixture to flow from the discharge port, through the fluid inlet channel, and into the inlet side of the cavity, wherein the fluid inlet channel is formed to facilitate a rotational flow of the refrigerant-oil fluid mixture in the cavity to apply a centrifugal force to separate the oil from the refrigerant; causing the separated oil to pool in the inlet side and flow through the fluid drain channel to the at least one oil reservoir, and causing the refrigerant to flow from the inlet side of the cavity through the conduit into the outlet side of the cavity, and through the fluid outlet channel to the associated refrigeration circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

The above, as well as other objects and advantages of the invention, will become readily apparent to those skilled in the art from reading the following detailed description of the preferred embodiment of the invention when considered in the light of the accompanying drawings in which:

FIG. 1 is a perspective view of a compressor showing an oil separator in section in accordance with an embodiment of the invention;

FIG. 2 is an enlarged fragmentary perspective view of the compressor of FIG. 1 with the oil separator shown in section along line 2-2 in FIG. 1;

FIG. 3 is an enlarged fragmentary perspective view of the compressor of FIG. 1 with the oil separator shown in section along line 3-3 in FIG. 1;

FIG. 4 is an enlarged fragmentary perspective view of the compressor of Fig.1 with the oil separator shown in section along line 4-4 in FIG. 1; and

FIG. 5 is an enlarged fragmentary perspective view of an oil separator according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, an are not intended to the scope of the invention in any manner. In respect of he methods disclosed, the steps presented are exemplary in nature, and thus, the order of t e steps is not necessary or critical.

FIGS. 1-4 show a fluid compressor 1 including an oil separator 10. The compressor 1 can be any type of fluid compressor such as a swashplate type compressor as disclosed in U.S. Pat. No. 6,431,053, hereby incorporated herein by reference in its entirety, or a scroll type compressor as disclosed in U.S. Pat. Nos. 6,543,243 and 6,382,941, each of which is hereby incorporated herein by reference in its entirety. Other compressors may be used as desired. In general, the compressor 1 includes a multi-piece housing 2 having a suction port (not shown) and a discharge port 4. The suction port provides a fluid communication path for a fluid to enter the compressor 1 from a refrigeration circuit (not shown) and be received by a means for compressing a fluid (not shown) disposed within an interior of the housing 2. The discharge port 4 provides a fluid communication path for the compressed fluid to exit the means for compressing and flow back into the refrigeration circuit through an outlet channel 9. In the embodiment shown, the fluid is a refrigerant including a lubricating oil for use in a refrigeration system (not shown) such as a heating, ventilating, and air conditioning system for a vehicle, for example. It should be understood that the refrigerant and the oil can be any suitable refrigerant and oil, as desired.

A pair of oil reservoirs 6 is formed in the housing 2 of the compressor 1. In the illustrated embodiment, the oil reservoirs 6 are formed to surround at least a portion of the housing 2 to form a pair of generally lung shaped cavities for holding a liquid lubricating oil for lubricating moving components disposed within the housing 2 of the compressor 1. An orifice 8 is disposed between each oil reservoir 6 and the interior of the housing 2 to facilitate the flow of the liquid oil from the oil reservoir 6 to the interior of the housing 2, and to minimize a gas recirculation through the compressor between the oil separator 10 and the interior of the housing 2 of the compressor 1. It should be understood that a single oil reservoir can be provided, or more than two oil reservoirs can be provided, as desired.

The oil separator 10 has a generally cylindrical cavity 12 formed in the housing 2 thereof. It should be understood that other shapes can be employed for the cavity 12 as desired. A longitudinal axis of the cylindrical cavity 12 is substantially parallel with a longitudinal axis of the compressor 1. It should be understood that the oil separator 10 can be formed as a separate component that is attached to the housing 2 of the compressor 1.

A sleeve 14 is disposed within the cavity 12 that includes a radially inwardly extending wall 16 to divide the cavity 12 between an inlet side 18 and an outlet side 20. It should be understood that the sleeve 14 can be disposed within the cavity at a variety of locations to provide a desired volume to the inlet side 18 and the outlet side 20, respectively. As illustrated in FIG. 5, a textured finish 29 can be formed on an interior surface of the inlet side 18 of the cylindrical cavity 12. The textured finish 29, such as a knurled surface, an anodized surface, or the like, increases a surface area of the interior surface, which maximizes an oil separation potential of the oil separator 10.

A conduit 22 such as a tube, for example, is provided that extends through the wall 16 having one end 24 disposed in the inlet side 18 and an opposite end 26 dispose in the outlet side 20 of the cylindrical cavity 12. The conduit 22 provides fluid communication between the inlet side 18 and the outlet side 20 of the cavity 12. The conduit 22 passes through the wall 16 substantially at a center point thereof to position the conduit 22 substantial concentric with the interior surface forming the cavity 12. It should be understood that a distance between the one end 24 of the conduit 22 and the wall 16 can be any distance, as desired. Additionally, a distance between the opposite end 26 of the conduit 22 and the wall 16 can be any selected distance to achieve a desired expansion characteristic of the fluid flowing therethrough. Further, a bell mouth 28 can be formed on the one end 24 of the conduit 22 as illustrated in FIG. 5. The bell mouth 28 facilitates the flow of the fluid into the conduit 22 to minimizes frictional losses and an associated pressure drop in the fluid flowing therethrough, which maximizes an efficiency of the compressor 1. Additionally, the bell mouth 28 causes the fluid to flow adjacent the interior surface forming the cavity 12 as the fluid flows past the bell mouth 28 prior to flowing into the conduit 22.

An inlet channel 30 is formed in the housing 2 that provides fluid communication between the discharge port 4 of the compressor 1 and the inlet side 18 of the oil separator 10. The inlet channel 30 is formed at an angle in respect of the interior surface of the inlet side 18 of the oil separator 10 to facilitate creation of a vortex fluid flow path therein. Favorable results have been obtained by locating an opening to the inlet channel 30 adjacent the wall 16 to maximize a distance between the opening to the inlet channel 30 and the one 24 of the conduit 22.

A pair of oil drain channels 32 is formed in the housing 2 that provides a fluid communication path for the liquid oil to flow from the inlet side 18 to the oil reservoirs 6. The oil drain channels 32 can be formed at a desired location to facilitate the flow of the liquid oil therethrough. Favorable results have been obtained by locating an opening of the drain channels 32 adjacent a bottom most portion of the inlet side 18 of the oil separator 10 in respect of a selected mounting position of the compressor 1. It should be understood that a single oil drain channel can be formed in the housing 2 that provides a fluid communication path between the inlet side 18 and one or more oil reservoirs 6.

An outlet channel 34 is formed in the housing 2 to provide a fluid communication path for the compressed refrigerant gas to flow from the outlet side 20 of the oil separator 10 and exit the compressor through the outlet channel 9 to the refrigeration circuit. It should be understood that an opening to the outlet channel 34 can be located at a desired location on the inner surface forming the outlet side 20 of the oil separator 10.

In operation, a refrigerant-oil fluid mixture flows through the suction chamber of the compressor 1 and enters the means for compressing the fluid disposed within the housing 2 of the compressor 1. The fluid is compressed and exhausted from the means for compressing to the discharge port 4. The fluid flows through the discharge port 4 and the inlet channel 30 into the inlet side 18 of the oil separator 10. The inlet channel 30 causes the fluid to enter the inlet side 18 of the oil separator 10 at in angle in respect of the interior surface of the inlet side 18 of the oil separator 10. Thus, a substantially vortex type flow of the fluid is created within the inlet side 18 of the oil separator 10, wherein the fluid repeatedly swirls around the conduit 22 as it flows from the inlet channel 30 toward the one end 24 of the conduit 22. The swirling movement of the fluid applies a centrifugal force on the oil in the fluid, thereby separating the liquid oil from the gas refrigerant. The textured surface 29 forming the inlet side 18 of the cavity 12 maximizes a surface area thereof to maximize the oil separating capability of the oil separator 10. The separated oil collects on the interior surface of the inlet side 18 of the cavity 12 and pools at the bottom most portion thereof.

The oil drain channels 32 are formed in the housing 2 of the compressor 1 having an opening to the oil drain channels 32 adjacent the bottom most portion of the cavity 12. The pooled oil flows through the drain channels 32 into the reservoirs 6. The oil can then flow from the reservoirs 6, through the orifices 8, and into the interior of the housing 2 for lubricating any moving parts disposed therein. The orifices 8 militate against a recirculation of the refrigerant through the oil drain channels 32 to the interior of the housing 2 of the compressor 1.

The oil is substantially separated from the refrigerant in the inlet side 18 of the oil separator 10. The refrigerant, substantially free of oil, flows from the inlet side 18 through the conduit 22 into the outlet side 20 of the oil separator 10. The bell mouth 28, illustrated in FIG. 5, can be formed on the end 24 of the conduit 22 to further facilitate the flow of the refrigerant from the inlet side 18 into the conduit 22. In particular, the bell mouth 28 is adapted to tune the flow of the refrigerant to minimize frictional losses, which maximizes the coefficient of performance of the compressor 1. Additionally, the bell mouth 28 causes the fluid to flow adjacent the interior surface forming the cavity 12 as the fluid flows past the bell mouth 28 prior to flowing into the conduit 22, which maximizes a contact between the fluid and the interior surface forming the cavity 12. The distance between the wall 16 and the end 26 of the conduit 22 is selected to achieve a desired expansion characteristic to the oil separator 10 for the refrigerant as it flows into the outlet side 20 of oil separator 10. The refrigerant exits the outlet side 20 of the oil separator through the outlet channel 34 to exit the compressor through the outlet channel 9 and flow into the refrigeration circuit.

It should be understood that the inlet side 18, outlet side 20, and conduit 22 cooperate to muffle the flow of the compressed refrigerant as it exits the compressor. The expansion and contraction of the refrigerant as it flows through the oil separator 12 enables the oil separator 10 act as a tunable muffler that can be adapted to minimize noise, vibration, and harshness (NVH) emanating from the compressor 1.

The forming of the oil reservoirs 6 and the oil separator 10 integrally with the housing 2 of the compressor 1 provides a compressor that can be configured to a number of applications. For example, the compressor 1 can be mounted at a plurality of positions such as the oil separator 10 located at a top most location in respect of the compressor 1, or can be mounted wherein the compressor 1 is rotated about its longitudinal axis to position the oil separator 10 forty-five degrees from the top most location. The oil reservoirs 6 and the oil separator 10 enable the compressor 1 to be mounted in a plurality of such positions without substantially affecting the performance of the oil separator 10. Additionally, it should be understood that the oil drain channels 34 can be formed at selected locations in the housing 2 to position the openings to the oil drain channels 34 at an optimized position for the intended mounting position of the compressor 1.

The fluid compressor 1 described herein includes an oil separator 10 and associated oil reservoirs 6 which minimize a space requirement for the compressor 1 while an oil separation efficiency and available mounting positions of the compressor 1 are maximized.

From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions. 

1. An oil separator for a fluid compressor comprising: a housing having a cavity formed therein; a wall disposed in the cavity to divide the cavity into an inlet side and an outlet side, the inlet side including a fluid inlet channel and at least one fluid drain channel, and the outlet side including a fluid outlet channel, wherein the inlet side of the cavity facilitates the separation of an oil from a fluid; and a conduit extending through the wall providing a fluid communication path between the inlet side and the outlet side of the cavity.
 2. The oil separator according to claim 1, wherein the cavity is generally cylindrical.
 3. The oil separator according to claim 1, wherein a surface of the cavity is textured to maximize a surface area thereof.
 4. The oil separator according to claim 1, wherein the fluid inlet channel in the inlet side of the cavity is in fluid communication with a discharge port of the fluid compressor.
 5. The oil separator according to claim 1, wherein the fluid inlet channel in the inlet side of the cavity is formed adjacent the wall.
 6. The oil separator according to claim 1, wherein the fluid inlet channel in the inlet side of the cavity is formed to facilitate a rotational fluid flow in the cavity.
 7. The oil separator according to claim 1 wherein one end of the conduit extends from the wall into the inlet side of the cavity and an opposite end of the conduit extends from the wall into the outlet side of the cavity.
 8. The oil separator according to claim 7, wherein the conduit includes a bell mouth formed at the one end of the conduit extending into the inlet side of the cavity.
 9. The oil separator according to claim 1, wherein the conduit is concentric with the cavity.
 10. The oil separator according to claim 1, wherein the fluid outlet channel formed in the outlet side of the cavity is adapted to be in fluid communication with a refrigeration circuit.
 11. A fluid compressor comprising: a housing having a discharge port and at least one oil reservoir formed therein; a generally cylindrical cavity formed in the housing forming an oil separator, the oil separator further comprising: a wall disposed in the cavity to divide the cavity into an inlet side and an outlet side, the inlet side including a fluid inlet channel providing fluid communication between the discharge port and the inlet side, and at least one fluid drain channel providing fluid communication between the at least one oil reservoir and the inlet side, the outlet side including a fluid outlet channel adapted to provide fluid communication between the outlet side and a refrigeration circuit, wherein the inlet side of the cavity facilitates the separation of an oil from a fluid; and a conduit extending through the wall providing a fluid communication path between the inlet side and the outlet side of the cavity.
 12. The fluid compressor according to claim 11, wherein the oil reservoir is formed to surround at least a portion of the housing of the compressor.
 13. The fluid compressor according to claim 11, wherein an orifice is formed in the housing of the compressor to provide a fluid communication path between the oil reservoir and an interior of the compressor.
 14. The fluid compressor according to claim 11, wherein the fluid inlet channel in the inlet side of the cavity is formed adjacent the wall.
 15. The fluid compressor according to claim 11, wherein the fluid inlet channel in the inlet side of the cavity is formed to facilitate a rotational fluid flow in the cavity.
 16. The fluid compressor according to claim 11, wherein a surface of the cavity is textured to maximize a surface area thereof.
 17. The fluid compressor according to claim 11, including a bell mouth formed at an end of the conduit disposed in the inlet side of the cavity.
 18. A method for separating a lubricant from a refrigerant in a fluid compressor comprising the steps of: providing a housing for the compressor having a generally cylindrical cavity, a discharge port, and at least one oil reservoir formed therein; providing a wall to divide the cavity into an inlet side and an outlet side, the inlet side including a fluid inlet channel providing fluid communication between the discharge port and the inlet side of the cavity, and at least one fluid drain channel providing fluid communication between the at least one oil reservoir and the inlet side of the cavity, the outlet side including a fluid outlet channel providing fluid communication between the outlet side of the cavity and an associated refrigeration circuit; providing a conduit extending through the wall providing a fluid communication path between the inlet side and the outlet side of the cavity; causing a refrigerant-oil fluid mixture to flow from the discharge port, through the fluid inlet channel, and into the inlet side of the cavity, wherein the fluid inlet channel is formed to facilitate a rotational flow of the refrigerant-oil fluid mixture in the cavity to apply a centrifugal force to separate the oil from the refrigerant. causing the separated oil to pool in the inlet side and flow through the fluid drain channel to the at least one oil reservoir, and causing the refrigerant to flow from the inlet side of the cavity through the conduit into the outlet side of the cavity, and through the fluid outlet channel to the associated refrigeration circuit.
 19. The method according to claim 18, further comprising the step of providing a textured surface to a surface of the inlet side of the cavity to maximize a surface area thereof.
 20. The method according to claim 18, further comprising the step of forming a bell mouth at an end of the conduit extending into the inlet side of the cavity. 